variance One Mth vs prior Month in row

[jasp]

Hi ALL,

heres my issue, have a prompt and user selects a year, and what appears in a crosstabs are 13 months ie months  dec -09 & the months jan - dec 2010 (total 13 months) in the column headings.

Say if i have sales member in a row, what I need in under the sales row to show the variance of one mth to the prior mth, like below.

                   Dec-09  Jan-2010  Feb 2010 March 2010 April 2010

Sales               10          15            22            30          5

Var prior mth                    5             7              8           -25

I know this is easy if the variance was in  a column heading, but how do you do it in a row calcuation. The prompt is dynamic....ie 2008 to 2010

Thanks , any help would be appreciated.

[paddhu]

Have you tried using running-difference function?

[jasp]

I believe the running difference function will create numerous rows , i wanted just one row with all the variances, please correct me if i am wrong...